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authorMiklos Szeredi <miklos@szeredi.hu>2005-09-09 16:10:28 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-09 17:03:45 -0400
commite5e5558e923f35839108a12718494ecb73fb782f (patch)
treec410d6826e9df13f7ea9e382a26589b66ec0989c /fs/fuse/dir.c
parent334f485df85ac7736ebe14940bf0a059c5f26d7d (diff)
[PATCH] FUSE - read-only operations
This patch adds the read-only filesystem operations of FUSE. This contains the following files: o dir.c - directory, symlink and file-inode operations The following operations are added: o lookup o getattr o readlink o follow_link o directory open o readdir o directory release o permission o dentry revalidate o statfs Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/fuse/dir.c')
-rw-r--r--fs/fuse/dir.c413
1 files changed, 413 insertions, 0 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
new file mode 100644
index 000000000000..a89730e70c58
--- /dev/null
+++ b/fs/fuse/dir.c
@@ -0,0 +1,413 @@
1/*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2005 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7*/
8
9#include "fuse_i.h"
10
11#include <linux/pagemap.h>
12#include <linux/file.h>
13#include <linux/gfp.h>
14#include <linux/sched.h>
15#include <linux/namei.h>
16
17static inline unsigned long time_to_jiffies(unsigned long sec,
18 unsigned long nsec)
19{
20 struct timespec ts = {sec, nsec};
21 return jiffies + timespec_to_jiffies(&ts);
22}
23
24static void fuse_lookup_init(struct fuse_req *req, struct inode *dir,
25 struct dentry *entry,
26 struct fuse_entry_out *outarg)
27{
28 req->in.h.opcode = FUSE_LOOKUP;
29 req->in.h.nodeid = get_node_id(dir);
30 req->inode = dir;
31 req->in.numargs = 1;
32 req->in.args[0].size = entry->d_name.len + 1;
33 req->in.args[0].value = entry->d_name.name;
34 req->out.numargs = 1;
35 req->out.args[0].size = sizeof(struct fuse_entry_out);
36 req->out.args[0].value = outarg;
37}
38
39static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
40{
41 if (!entry->d_inode || is_bad_inode(entry->d_inode))
42 return 0;
43 else if (time_after(jiffies, entry->d_time)) {
44 int err;
45 int version;
46 struct fuse_entry_out outarg;
47 struct inode *inode = entry->d_inode;
48 struct fuse_inode *fi = get_fuse_inode(inode);
49 struct fuse_conn *fc = get_fuse_conn(inode);
50 struct fuse_req *req = fuse_get_request_nonint(fc);
51 if (!req)
52 return 0;
53
54 fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg);
55 request_send_nonint(fc, req);
56 version = req->out.h.unique;
57 err = req->out.h.error;
58 fuse_put_request(fc, req);
59 if (err || outarg.nodeid != get_node_id(inode) ||
60 (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
61 return 0;
62
63 fuse_change_attributes(inode, &outarg.attr);
64 inode->i_version = version;
65 entry->d_time = time_to_jiffies(outarg.entry_valid,
66 outarg.entry_valid_nsec);
67 fi->i_time = time_to_jiffies(outarg.attr_valid,
68 outarg.attr_valid_nsec);
69 }
70 return 1;
71}
72
73static struct dentry_operations fuse_dentry_operations = {
74 .d_revalidate = fuse_dentry_revalidate,
75};
76
77static int fuse_lookup_iget(struct inode *dir, struct dentry *entry,
78 struct inode **inodep)
79{
80 int err;
81 int version;
82 struct fuse_entry_out outarg;
83 struct inode *inode = NULL;
84 struct fuse_conn *fc = get_fuse_conn(dir);
85 struct fuse_req *req;
86
87 if (entry->d_name.len > FUSE_NAME_MAX)
88 return -ENAMETOOLONG;
89
90 req = fuse_get_request(fc);
91 if (!req)
92 return -ERESTARTNOINTR;
93
94 fuse_lookup_init(req, dir, entry, &outarg);
95 request_send(fc, req);
96 version = req->out.h.unique;
97 err = req->out.h.error;
98 if (!err) {
99 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
100 &outarg.attr, version);
101 if (!inode) {
102 fuse_send_forget(fc, req, outarg.nodeid, version);
103 return -ENOMEM;
104 }
105 }
106 fuse_put_request(fc, req);
107 if (err && err != -ENOENT)
108 return err;
109
110 if (inode) {
111 struct fuse_inode *fi = get_fuse_inode(inode);
112 entry->d_time = time_to_jiffies(outarg.entry_valid,
113 outarg.entry_valid_nsec);
114 fi->i_time = time_to_jiffies(outarg.attr_valid,
115 outarg.attr_valid_nsec);
116 }
117
118 entry->d_op = &fuse_dentry_operations;
119 *inodep = inode;
120 return 0;
121}
122
123int fuse_do_getattr(struct inode *inode)
124{
125 int err;
126 struct fuse_attr_out arg;
127 struct fuse_conn *fc = get_fuse_conn(inode);
128 struct fuse_req *req = fuse_get_request(fc);
129 if (!req)
130 return -ERESTARTNOINTR;
131
132 req->in.h.opcode = FUSE_GETATTR;
133 req->in.h.nodeid = get_node_id(inode);
134 req->inode = inode;
135 req->out.numargs = 1;
136 req->out.args[0].size = sizeof(arg);
137 req->out.args[0].value = &arg;
138 request_send(fc, req);
139 err = req->out.h.error;
140 fuse_put_request(fc, req);
141 if (!err) {
142 if ((inode->i_mode ^ arg.attr.mode) & S_IFMT) {
143 make_bad_inode(inode);
144 err = -EIO;
145 } else {
146 struct fuse_inode *fi = get_fuse_inode(inode);
147 fuse_change_attributes(inode, &arg.attr);
148 fi->i_time = time_to_jiffies(arg.attr_valid,
149 arg.attr_valid_nsec);
150 }
151 }
152 return err;
153}
154
155static int fuse_revalidate(struct dentry *entry)
156{
157 struct inode *inode = entry->d_inode;
158 struct fuse_inode *fi = get_fuse_inode(inode);
159 struct fuse_conn *fc = get_fuse_conn(inode);
160
161 if (get_node_id(inode) == FUSE_ROOT_ID) {
162 if (current->fsuid != fc->user_id)
163 return -EACCES;
164 } else if (time_before_eq(jiffies, fi->i_time))
165 return 0;
166
167 return fuse_do_getattr(inode);
168}
169
170static int fuse_permission(struct inode *inode, int mask, struct nameidata *nd)
171{
172 struct fuse_conn *fc = get_fuse_conn(inode);
173
174 if (current->fsuid != fc->user_id)
175 return -EACCES;
176 else {
177 int mode = inode->i_mode;
178 if ((mask & MAY_WRITE) && IS_RDONLY(inode) &&
179 (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
180 return -EROFS;
181 if ((mask & MAY_EXEC) && !S_ISDIR(mode) && !(mode & S_IXUGO))
182 return -EACCES;
183 return 0;
184 }
185}
186
187static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
188 void *dstbuf, filldir_t filldir)
189{
190 while (nbytes >= FUSE_NAME_OFFSET) {
191 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
192 size_t reclen = FUSE_DIRENT_SIZE(dirent);
193 int over;
194 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
195 return -EIO;
196 if (reclen > nbytes)
197 break;
198
199 over = filldir(dstbuf, dirent->name, dirent->namelen,
200 file->f_pos, dirent->ino, dirent->type);
201 if (over)
202 break;
203
204 buf += reclen;
205 nbytes -= reclen;
206 file->f_pos = dirent->off;
207 }
208
209 return 0;
210}
211
212static int fuse_checkdir(struct file *cfile, struct file *file)
213{
214 struct inode *inode;
215 if (!cfile)
216 return -EIO;
217 inode = cfile->f_dentry->d_inode;
218 if (!S_ISREG(inode->i_mode)) {
219 fput(cfile);
220 return -EIO;
221 }
222
223 file->private_data = cfile;
224 return 0;
225}
226
227static int fuse_getdir(struct file *file)
228{
229 struct inode *inode = file->f_dentry->d_inode;
230 struct fuse_conn *fc = get_fuse_conn(inode);
231 struct fuse_req *req = fuse_get_request(fc);
232 struct fuse_getdir_out_i outarg;
233 int err;
234
235 if (!req)
236 return -ERESTARTNOINTR;
237
238 req->in.h.opcode = FUSE_GETDIR;
239 req->in.h.nodeid = get_node_id(inode);
240 req->inode = inode;
241 req->out.numargs = 1;
242 req->out.args[0].size = sizeof(struct fuse_getdir_out);
243 req->out.args[0].value = &outarg;
244 request_send(fc, req);
245 err = req->out.h.error;
246 fuse_put_request(fc, req);
247 if (!err)
248 err = fuse_checkdir(outarg.file, file);
249 return err;
250}
251
252static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
253{
254 struct file *cfile = file->private_data;
255 char *buf;
256 int ret;
257
258 if (!cfile) {
259 ret = fuse_getdir(file);
260 if (ret)
261 return ret;
262
263 cfile = file->private_data;
264 }
265
266 buf = (char *) __get_free_page(GFP_KERNEL);
267 if (!buf)
268 return -ENOMEM;
269
270 ret = kernel_read(cfile, file->f_pos, buf, PAGE_SIZE);
271 if (ret > 0)
272 ret = parse_dirfile(buf, ret, file, dstbuf, filldir);
273
274 free_page((unsigned long) buf);
275 return ret;
276}
277
278static char *read_link(struct dentry *dentry)
279{
280 struct inode *inode = dentry->d_inode;
281 struct fuse_conn *fc = get_fuse_conn(inode);
282 struct fuse_req *req = fuse_get_request(fc);
283 char *link;
284
285 if (!req)
286 return ERR_PTR(-ERESTARTNOINTR);
287
288 link = (char *) __get_free_page(GFP_KERNEL);
289 if (!link) {
290 link = ERR_PTR(-ENOMEM);
291 goto out;
292 }
293 req->in.h.opcode = FUSE_READLINK;
294 req->in.h.nodeid = get_node_id(inode);
295 req->inode = inode;
296 req->out.argvar = 1;
297 req->out.numargs = 1;
298 req->out.args[0].size = PAGE_SIZE - 1;
299 req->out.args[0].value = link;
300 request_send(fc, req);
301 if (req->out.h.error) {
302 free_page((unsigned long) link);
303 link = ERR_PTR(req->out.h.error);
304 } else
305 link[req->out.args[0].size] = '\0';
306 out:
307 fuse_put_request(fc, req);
308 return link;
309}
310
311static void free_link(char *link)
312{
313 if (!IS_ERR(link))
314 free_page((unsigned long) link);
315}
316
317static void *fuse_follow_link(struct dentry *dentry, struct nameidata *nd)
318{
319 nd_set_link(nd, read_link(dentry));
320 return NULL;
321}
322
323static void fuse_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
324{
325 free_link(nd_get_link(nd));
326}
327
328static int fuse_dir_open(struct inode *inode, struct file *file)
329{
330 file->private_data = NULL;
331 return 0;
332}
333
334static int fuse_dir_release(struct inode *inode, struct file *file)
335{
336 struct file *cfile = file->private_data;
337
338 if (cfile)
339 fput(cfile);
340
341 return 0;
342}
343
344static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
345 struct kstat *stat)
346{
347 struct inode *inode = entry->d_inode;
348 int err = fuse_revalidate(entry);
349 if (!err)
350 generic_fillattr(inode, stat);
351
352 return err;
353}
354
355static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
356 struct nameidata *nd)
357{
358 struct inode *inode;
359 int err = fuse_lookup_iget(dir, entry, &inode);
360 if (err)
361 return ERR_PTR(err);
362 if (inode && S_ISDIR(inode->i_mode)) {
363 /* Don't allow creating an alias to a directory */
364 struct dentry *alias = d_find_alias(inode);
365 if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {
366 dput(alias);
367 iput(inode);
368 return ERR_PTR(-EIO);
369 }
370 }
371 return d_splice_alias(inode, entry);
372}
373
374static struct inode_operations fuse_dir_inode_operations = {
375 .lookup = fuse_lookup,
376 .permission = fuse_permission,
377 .getattr = fuse_getattr,
378};
379
380static struct file_operations fuse_dir_operations = {
381 .read = generic_read_dir,
382 .readdir = fuse_readdir,
383 .open = fuse_dir_open,
384 .release = fuse_dir_release,
385};
386
387static struct inode_operations fuse_common_inode_operations = {
388 .permission = fuse_permission,
389 .getattr = fuse_getattr,
390};
391
392static struct inode_operations fuse_symlink_inode_operations = {
393 .follow_link = fuse_follow_link,
394 .put_link = fuse_put_link,
395 .readlink = generic_readlink,
396 .getattr = fuse_getattr,
397};
398
399void fuse_init_common(struct inode *inode)
400{
401 inode->i_op = &fuse_common_inode_operations;
402}
403
404void fuse_init_dir(struct inode *inode)
405{
406 inode->i_op = &fuse_dir_inode_operations;
407 inode->i_fop = &fuse_dir_operations;
408}
409
410void fuse_init_symlink(struct inode *inode)
411{
412 inode->i_op = &fuse_symlink_inode_operations;
413}
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